Malate Dehydrogenase (MDH) (EC 1.1.1.37) reversibly converts L-Malate into oxaloacetate in the presence of NAD+. In eukaryotic cells, malate dehydrogenase has 2 isoforms, MDH1 and MDH2. MDH1 is cytosolic and participates in the malate-aspartate shuttle, which transports malate into the mitochondria. Malate will then be utilized for the generation of ATP. MDH2, on the other hand, is a mitochondrial enzyme that participates in the citric acid cycle. MDH2 activity is increased in some neurodegenerative diseases such as Alzheimer's disease, and abnormal MDH activity in serum can serve as a diagnostic tool for severe liver damage (e.g. Hepatocellular carcinoma). Assay Genie's Malate Dehydrogenase Activity Assay Kit (Fluorometric) provides a quick and easy method for monitoring MDH activities in a wide variety of samples. In this assay, MDH converts malate into intermediate products, which will further react with forming a fluorophore (Ex/Em=535/587nm). The kit is simple, sensitive and high-throughput adaptable and can detect as low as 40 µU of MDH activity.

Figure: (a) NADH Standard Curve; (b) Malate Dehydrogenase activities in rat muscle extract (0.011 µg protein), Jurkat cell lysate (0.026 µg protein), Saccharomyces mitochondria (0.05 µg) & MDH positive control; (c) Specific MDH activities in rat muscle extract, Jurkat cell lysate and yeast Mitochondria. Assays were performed following the kit protocol.